Apparatus and system to drill a bore using a laser

ABSTRACT

A system to extend a lateral bore section using laser light comprises a first umbilical connected to a deflection member having a drive gear, a lateral exit port and at least one deployable seal intermediate a proximal end and the lateral exit port, and a second umbilical having an exterior movable by the drive member through a pathway of the deflection member ending at the lateral exit port to controllably advance a drill head connected to a leading end of the second umbilical. Optical fibers of the second umbilical transmit laser light from a surface end to optical elements in the drill head that condition laser light for heating a targeted portion of a bore wall. The first umbilical positions the deflection member within a primary bore section, and the second umbilical is controllably advanced to extend a lateral bore by the drive gear of the deflection member.

STATEMENT OF RELATED APPLICATIONS

This application claims priority to and depends to InternationalPCT/US2012/055768 filed on 17 Sep. 2012, which claims priority to anddepends from Hungarian application no. P1100517 filed on 15 Sep. 2011,and Hungarian application no. P1100665 filed on 1 Dec. 2011.

BACKGROUND

1. Field of Invention

The present invention relates to the drilling of earthen bores torecover fluids residing in subterranean geologic formations. Morespecifically, the present invention relates to an apparatus and systemto extend a bore section into a geologic formation using a laserdrilling apparatus.

2. Background of the Related Art

Borehole systems are drilled into the earth's crust to penetratesubsurface geologic formations bearing a formation fluid, such as water,oil or gas, to facilitate the production of the formation fluid to thesurface. A bore system may comprise a single bore surrounded by a borewall or, alternately, a primary bore having one or more intersectinglateral bores surrounded, along with the primary bore, by a common borewall.

A bore system may be bored in the earth's crust using conventionalmechanical drilling rigs at the earth's surface to rotate a drill bit ata leading end of a drill string extending from the rig. Some rigs rotatethe entire drill string, which may comprise a plurality of segments orstands of drill pipe threadedly coupled to form an elongate drillstring. The drill string can be made up by adding segments as the drillstring is extended deeper into the earth's crust or laid down byremoving segments as the drill string is withdrawn from the earth'scrust. The rotation of the drill string and the drill bit at the leadingend of the drill string, while urging the drill bit against an end of aprimary bore or lateral bore section to be extended, breaks apart rockengaged by the drill bit.

Alternately, a drill string may comprise a mud motor proximal to theleading end and hydraulically powered by pressurized fluid providedthrough the center of the drill string to rotate a drill bit coupled tothe mud motor to break apart the rock engaged by the drill bit. With amud motor or a conventional drill string, drill cuttings are removedfrom the portion of the bore to be extended by circulating working fluiddown the drill string and back to the earth's surface through theannulus between the drill string and the wall of the bore.

Still other systems and methods for extending a section of a bore systeminclude the use of a high-pressure jet to mechanically fracture rockwithin a fluid path adjacent to a liquid jet at the leading end of adrill string. High-pressure “jet” drilling may include the removal ofdebris resulting from the drilling process by circulating fluid into andfrom the portion of the borehole system being extended. For bestresults, the jet path between the liquid jet nozzle and the portion ofthe bore wall to be jet blasted should be as short as possible to imparta maximum amount of liquid kinetic energy on the targeted portion of thebore wall to be extended.

A method for extending a section of a bore system includes the use of alaser drill head connected to a leading end of a drill string. The drillhead is used to introduce laser light into the bore section to heat,melt and/or vaporize at least some components of the geologic formationexposed to a laser path adjacent to the drill head. Unlike aconventional drilling system that forcibly engages a drill bit againstthe wall of a bore section, a laser drilling process generally requiresthat the portion of the drill head from which the laser light is emittedremains in close proximity to, but not in actual contact with, thetargeted portion of the wall of the bore section to be extended. A laserpath between the drill head and a targeted portion of the bore wall tobe extended is irradiated using the drill head.

Extending bore sections using laser drill heads generally requires thatthe portion of the bore section intermediate the drill head and thetargeted portion of the wall of the bore section be cleared oflaser-obstructing material. Unwanted accumulation of debris on laseremitting portions of the drill head impairs drilling performance byobstructing efficient transmission of emitted laser light to impinge onthe targeted portion of the wall of the bore section to be extended.Optimal results can be obtained when the laser emitting drill head canbe controllably advanced within the bore section as debris is removed,and when contaminants can be either prevented from being deposited ontoor in the way of laser emitting portions of the drill head or removedfrom laser emitting portions of the drill head to maintain drillingperformance.

BRIEF SUMMARY OF THE INVENTION

One embodiment of the present invention provides a system tocontrollably advance a laser emitting drill head to extend a targetedportion of a wall of a bore section that is lateral to and intersects aprimary bore. The system comprises a first umbilical connected to adeflection member having proximal end, a distal end, a gear drive, alateral exit port and an umbilical pathway adjacent to the drive gearand intersecting the lateral exit port. The first umbilical is used toposition the deflection member within a primary bore and compriseseither a fluid conduit or an electrically conductive member to deliverpressurized fluid or electrical current, respectively, to a motor in thedeflection member to operate the drive gear. The first umbilical is usedto position the deflection member within a primary bore adjacent to adesired lateral bore to be created and/or extended using the system ofthe present invention. The deflection member receives and cooperateswith a second umbilical having a fluid conduit and a plurality ofoptically transmitting fibers and connected at a leading end of thesecond umbilical to a drill head.

The drill head comprises at least one optical element to receive laserlight from a plurality of optically transmitting fibers within thesecond umbilical and to emit laser light to impinge on a targetedportion of a bore wall. The drill head further comprises a fluid jumperconduit connected to a fluid nozzle to receive pressurized fluid fromthe fluid conduit of the second umbilical. The drill head may be adaptedto inject a stream of the fluid to displace laser-obstructing materialsfrom a laser light path intermediate the optical element and thetargeted portion of the bore wall. The drill head may also be adapted toinject a stream of the fluid to protect and cool a laser emittingportion of the drill head, as will be discussed in greater detail below.The second umbilical comprises an exterior portion disposed generallyproximal to the drill head that is shaped and sized to be engaged anddriven by one or more drive gears driven by the motor of the deflectionmember. In one embodiment, the exterior portion of the second umbilicalcomprises a series of corrugations having a generally uniform spacingand a generally uniform radial height for engagement by the one or moredrive gears of the deflection member such that, upon operation of theone or more drive gears, the second umbilical is controllably advancedthrough the umbilical pathway of the deflection member. This cooperativearrangement between the deflection member at the leading end of thefirst umbilical and the exterior portion of the second umbilical that isproximal to the leading end of the second umbilical enables thelaser-emitting drill head at the leading end of the second umbilical tobe controllably advanced to extend a targeted portion of the bore walladjacent to the lateral exit port of the deflection member. In anotherembodiment, the exterior portion of the second umbilical comprises aspirally-wound thread having a generally uniform pitch and height forengagement with a mating spirally-wound thread within one or more drivegears of the deflection member such that, upon operation of the motor torotate the one or more drive gears, the second umbilical is controllablymoved through the umbilical pathway of the deflection member tocontrollably advance the drill head connected to the leading end of thesecond umbilical to extend targeted portion of the bore wall adjacent tothe lateral exit port of the deflection member.

It may be desirable to isolate or to substantially isolate portions ofthe bore system being extended from other portions of the bore system inorder to control the environment proximal to the drill head. Embodimentsof the system of the present invention include a deflection member thatmay be adapted to sealably engage a wall of the primary bore and tothereby facilitate the displacement of laser-obstructing materialswithin the primary bore from a laser light path intermediate the laseremitting portion of the drill head being controllably advanced by thedrive gear and a targeted portion of a bore wall to be extended usingthe drill head. In one embodiment, the system comprises a deflectionmember having a circumferentially deployable seal intermediate theproximal end and the lateral exit port of the deflection member. Thecircumferentially deployable seal is connected, through a valve, to afluid conduit within the first umbilical that provides, upon opening ofthe valve, pressurized fluid to expand the circumferentially deployableseal radially outwardly from the deflection member to engage and sealagainst the wall of the primary bore in which the deflection member ispositioned using the first umbilical. In one embodiment, the firstumbilical may comprise a second fluid conduit to provide displacementfluid into the primary bore at a location distal to thecircumferentially deployable seal, that is, at a location opposite thedeployable seal from the proximal end of the deflection member, todisplace laser-obstructing materials from a laser light pathintermediate the drill head connected to the second umbilical and thetargeted portion of the bore wall adjacent thereto. Either the firstfluid conduit or the second fluid conduit, if any, of the firstumbilical provides power fluid to operate the motor that drives the oneor more drive gears of the deflection member.

In another embodiment, the system may comprise a deflection memberhaving a proximal circumferentially deployable seal, intermediate theproximal end and the lateral exit port of the deflection member, and adistal circumferentially deployable seal intermediate the lateral exitport and the distal end of the deflection member. The proximal anddistal circumferentially deployable seals may be connected, through oneor more valves, to a fluid conduit within the first umbilical thatprovides, upon opening of the one or more valves, pressurized fluid toexpand the proximal and distal circumferentially deployable sealsradially outwardly from the deflection member to engage and seal againstthe wall of the primary bore in which the deflection member ispositioned using the first umbilical. The first umbilical may alsocomprise a second fluid conduit to provide displacement fluid into theprimary bore at a location intermediate the proximal and distalcircumferentially deployable seals of the deflection member to displacelaser-obstructing materials from a laser light path intermediate thedrill head connected to the second umbilical and the targeted portion ofthe bore wall adjacent thereto. The deflection member may includefeatures to assist in removal of laser obstructing materials trappedbetween the deployed proximal and distal circumferentially deployableseals. For example, a distal circumferentially deployable seal bypassconduit within the deflection member may enable laser-obstructing fluidtrapped intermediate the proximal and distal circumferentiallydeployable seals to be displaced to a portion of the primary bore thatis distal to the distal circumferentially deployable seal of thedeflection member. An equalization bypass conduit within the deflectionmember may enable fluid within a portion of the primary bore distal tothe deflection member to be displaced to the portion of the primary boreproximal to the deflection member to equalize the pressure above andbelow, or proximal to and distal to, the deflection member. Acombination of a distal circumferentially deployable seal bypass conduitand an equalization conduit within a deflection member enables both thedisplacement of laser-obstructing material trapped intermediate theproximal and distal circumferentially deployable seals to the portion ofthe primary bore distal to the deflection member and the equalization ofpressure between the portion of the primary bore distal to thedeflection member and the portion of the primary bore proximal to thedeflection member.

Another embodiment of the system comprises a deflection member having anon-circumferential deployable seal surrounding the lateral exit portthrough which the umbilical pathway extends. The non-circumferentialdeployable seal comprises a sealing surface that, upon deployment of theseal, engages the wall of the primary bore to surround the targetedportion of the bore wall and isolate it from the primary bore except forthe lateral exit port for the umbilical pathway through the deflectionmember. The sealing surface of the non-circumferential deployable sealsurrounds the lateral exit portion of the deflection member and wrapsaround a portion of the deflection member. Displacing fluid provided todisplace laser-obstructing material from the laser light pathintermediate the drill head, at the leading end of the second umbilicalmovable within the umbilical pathway of the deflection member, and thetargeted portion of the bore wall is, during operation of the drillhead, forced to move from a lateral bore being extended and through theumbilical pathway to prevent laser-obstructing fluid from re-enteringthe laser light path.

The system and apparatus of the present invention facilitate theunimpeded impingement of laser light on a targeted portion of a borewall to be extended. The formation materials that make up the bore wallare heated by impingement of laser light emitted from the drill head.Globules of melted formation materials are formed and then swept fromthe bore wall by continued injection of the laser conductive material,such as clear liquid or gas. Depending on the composition of theformation and fluid residing therein, some components of the formationmay vaporize within the bore section, but most solid components willburn, vaporize or melt. Dust, molten formation components, and fragmentsand bits of formation components, in addition to vaporized remnants offormation fluids, are generated by the use of laser light to extend abore section. These contaminants can impinge on and adhere to, mar orotherwise tarnish the laser emitting portion of the drill head,resulting in an overall loss of drilling efficiency due to impairment ofunobstructed laser light transmission from the drill head to thetargeted portion of the bore wall.

In another embodiment, the present invention provides a drill head toextend a bore section into a subsurface geologic formation. The drillhead is connectable to and positioned within a bore using an umbilical.The drill head comprises an optical element to receive laser light fromoptically transmitting fibers within the umbilical and to emit laserlight to impinge on a targeted portion of a bore wall to be extendedthereby. The drill head is further connectable to a fluid conduit withinthe umbilical and comprises a fluid nozzle connected to the fluidconduit to inject a fluid stream directed generally adjacent to a laseremitting portion of the drill head to provide a protective barrieragainst debris impinging upon the laser emitting portion.

In another embodiment, the present invention provides a drill head toextend a bore section into a subsurface geologic formation. The drillhead is connectable to and positioned within a bore using an umbilical.The drill head comprises an optical element to receive laser light fromoptically transmitting fibers within the umbilical and to emit laserlight to impinge on a targeted portion of a bore wall to be extendedthereby. The drill head is further connectable to a leading end of afluid conduit within the umbilical and comprises a fluid jumper conduitterminating at a fluid nozzle to receive fluid provided to the nozzlefrom the fluid conduit and through the fluid jumper conduit if the drillhead. The fluid nozzle injects a fluid stream immediately anterior tothe laser emitting portion of the drill head. The fluid nozzle maydispose the fluid stream to impinge on the laser emitting portion of thedrill head or it may dispose the fluid stream to a position immediatelyadjacent to the laser emitting portion. In one embodiment, a transparentbarrier is positioned on the drill head and within a laser light pathextending from the laser emitting portion of the drill head. In thisembodiment, the fluid stream injected from the fluid nozzle is disposedimmediately anterior to and/or to impinge on the transparent barrier toprovide an additional protective barrier against debris impinging uponthe transparent barrier. Additionally, the fluid stream injected at thefluid nozzle provides a stream of fluid to remove heat from thetransparent barrier on the drill head or from the laser emitting portionof the drill head, and the fluid stream may impinge upon and removedebris from the transparent barrier or the laser emitting portion toprevent the debris from adhering to the transparent barrier or the laseremitting portion.

In another embodiment, the present invention provides a drill head toextend a bore section into a subsurface geologic formation. The drillhead is connectable to a leading end of an umbilical and positionablewithin an earthen bore using the umbilical. The drill head comprises anoptical element to receive laser light from optically transmittingfibers within the umbilical and emits laser light from the opticalelement to impinge on a targeted portion of a bore wall to be extendedthereby. The drill head is further connectable to a leading end of afluid conduit within the umbilical and comprises a fluid jumper conduitterminating at a fluid nozzle to receive fluid provided through thefluid conduit and to inject a fluid stream into the bore sectionimmediately anterior to the laser emitting portion of the drill head.The nozzle comprises an opening through which the injected fluid exitsto displace a movable protective member disposed immediately anterior tothe laser emitting portion of the drill head from a first position,generally shielding the laser emitting portion of the drill head fromdebris, to a second position providing a laser light path through whichlaser light may pass to impinge on a targeted portion of a bore wall. Inthe first position, the movable protective member obstructs debris fromcontacting the laser emitting portion of the drill head, and in thesecond position, the protective member is removed from the obstructingposition to permit laser light emitted from the laser emitting portionof the drill head to impinge on a targeted portion of a bore walladjacent to the drill head. In one embodiment, the protective membercomprises a unitary portion that is biased towards the first,obstructing position using a spring element. In another embodiment, theprotective member comprises a plurality of cooperating portions, eachbiased towards a first, obstructing position using a spring element. Inanother embodiment, the protective member comprises a unitary portionthat is spring biased towards the first, obstructing position using anelastomeric member such as, for example, a temperature-resistant rubberor rubberized element. In another embodiment, the protective member maycomprise a plurality of protective member portions, each spring biasedtowards a first, obstructing position by elastomeric members such as,for example, a plurality of rubber or rubberized elements. The unitaryprotective member may be fastened to a drill head structure, which is aportion of or an extension of the drill head generally adjacent to aleading end of the drill head proximal to the laser emitting portion ofthe drill head. Where the protective member comprises a plurality ofprotective member portions, the plurality of protective member portionsmay be fastened to the drill head structure. The protective member orprotective member portions may be formed of a rigid,temperature-resistant material such as metal or ceramic, and may becoupled to the drill head structure through a hinge to facilitate thedisplacement of the protective member from the first, protectingposition anterior to the laser emitting portion of the drill head to asecond, removed position to open a laser light path from the laseremitting portion to the targeted portion of a bore wall. Where theprotective member is elastomeric, a hinge or other coupling may not beneeded if the fluid pressure brought to bear on the protective member bythe fluid nozzle disposed adjacent to the protective member issufficient to displace the protective member from the first position tothe second position.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic illustrating an embodiment of a system of thepresent invention.

FIG. 2 is perspective view of an alternative spool that can be used tostore an umbilical of a system of the present invention.

FIG. 3 is a top view of a second alternative spool that can be used tostore an umbilical of a system of the present invention.

FIG. 4 is a perspective view of a portion of an embodiment of anapparatus, a drill head connected to an umbilical, which can be used toimplement one embodiment of the system of the present invention.

FIG. 5 is a sectional elevation view of an embodiment of a portion ofthe system of FIG. 1 having a deflection member positioned using a firstumbilical and having an umbilical pathway and a drive gear therein toreceive and engage, respectively, a second umbilical.

FIG. 6 is a side sectional elevation view of an alternative embodimentof the deflection member of the system of the present invention.

FIG. 7 is a frontal elevation view of the alternative embodiment of thedeflection member of FIG. 6.

FIG. 8 is a top sectional view of the alternative embodiment of thedeflection member of FIGS. 6 and 7.

FIG. 9 is a section view of an embodiment of a drill head of the presentinvention having a fluid conduit connected to a plurality of fluidnozzles to inject a plurality of fluid streams to protect a plurality oflaser emitting portions of the drill head from contact by debrisgenerated by the laser drilling process.

FIG. 10 is a section view of an embodiment of a drill head of thepresent invention having a fluid conduit connected to a plurality offluid nozzles to inject a plurality of fluid streams to protect atransparent member disposed on the drill head and within the laser lightpath intermediate a laser emitting portion of the drill head and atargeted portion of a bore wall.

FIG. 11 is a section view of an embodiment of a drill head of thepresent invention having a plurality of laser emitting portionsprotected from debris within the bore in which the drill head ispositioned by a plurality of pivoting protective members in a closedposition and movable to an open position by the introduction of fluidpressure adjacent to the laser emitting portions.

FIG. 12 is an enlarged view of one of the laser emitting portions of theembodiment of the drill head of FIG. 11 protected from debris by apivotable protective member in a closed position.

FIG. 13 is the enlarged view of FIG. 12 after fluid is introducedthrough a nozzle adjacent to the laser emitting portion of the drillhead to pivot the protective member from the closed position of FIGS. 11and 12 to an open position to facilitate the impingement of laser lightfrom the laser emitting portion of the drill head to a targeted portionof a bore wall.

FIG. 14 is an alternative embodiment of the drill head of FIGS. 11-13comprising a protective member comprising a plurality of cooperatingprotective member portions in a closed position to obstruct the emissionof laser light from the laser emitting portion of a drill head and toprotect the laser emitting portion from debris in the bore.

FIG. 15 is the alternative embodiment of FIG. 14 after fluid pressure isintroduced through a nozzle adjacent the laser emitting portion of thedrill head to deform the protective member portions from the closedconfiguration to an open configuration.

DETAILED DESCRIPTION

One embodiment of the present invention provides an apparatus and systemto extend an earthen bore section comprising a first elongate umbilicalto position a deflection member within a primary bore and a secondelongate umbilical connected at a leading end to a drill head. Thesecond umbilical and the drill head cooperate with the deflection memberto position and controllably advance the drill head to extend a lateralbore intersecting the primary bore. The first umbilical includes a fluidconduit to pressurize, expand and deploy one or more deployable seals onthe deflection member to engage and seal against the wall of the bore.The second umbilical also includes a fluid conduit to provide fluid tothe drill head. In one aspect, the fluid provided to the drill headthrough the second umbilical displaces laser-obstructing materials froma laser light path intermediate a laser emitting portion of the drillhead and a targeted portion of a bore wall to be extended using thedrill head. The second umbilical further comprises a plurality ofoptically transmitting fibers to transmit laser light from a laser lightgenerator at the earth's surface to an optical element within the drillhead. The laser light is emitted from the optical element to impinge onthe targeted portion of the bore wall.

In one embodiment, the first umbilical and the second umbilical are eachstored on and fed into an earthen bore system from a reel, a spool orother storage device. A storage device on which an umbilical may bewound or coiled facilitates transportation of the umbilical to and fromthe surface location of the entry to the bore system to be extendedthereby. The storage device may be rotated in a first direction to feedan umbilical stored thereon into a bore system and to position thedeflection member coupled to the leading end of the first umbilical, orto position the drill head coupled to the leading end of the secondumbilical, within the earthen. The storage device may be rotated in areversed direction to retrieve the umbilical from the bore system andback onto the storage device.

A storage device may be connected to a rotatable fluid coupling that iscoupled to a surface end of the fluid conduit of the umbilical tofacilitate the flow of fluid from a fluid source at the earth's surfaceto a surface end of the fluid conduit of the umbilical. The fluid, whichmay be liquid or pressurized gas, is delivered through a fluid conduitwithin an umbilical to, for the first umbilical, the deflection memberconnected to the leading end of the first umbilical or, for the secondumbilical, to the drill head connected to the leading end of the secondumbilical. In embodiments of an umbilical having a second fluid conduitin addition to a first fluid conduit, an umbilical storage device may beconnected to a second rotatable fluid coupling that receives a secondfluid from a storage device on the surface connected to a surface end ofthe second fluid conduit.

Similarly, the storage device may be connected to a rotatable opticaltransmission coupling connected to a surface end of the optical fibersof the second umbilical to facilitate the transmission of laser lightfrom a laser generator on the earth's surface to a surface end of theoptically transmitting fibers of the second umbilical. The laser lightis transmitted through the optical fibers of the second umbilical tooptical elements in the drill head connected to the leading end of thesecond umbilical. The rotatable couplings may be connected to and usedwith the umbilical storage device to accommodate rotary movement of theumbilical storage device relative to the earth's surface while providinga continuous supply of fluid, laser light and even a second fluidwithout unwanted twisting or binding of the umbilical. Alternately, thelaser generator may be disposed within the center of the spool aboutwhich the umbilical is wound or coiled.

The first umbilical comprises a leading end, to which the deflectionmember is connected, for being introduced into the bore system. Thefirst umbilical storage device rotates to feed out the first umbilicalinto the bore system in an amount sufficient to position the drill headat the leading end of the first umbilical at a desired lateral boresection site. The deflection member is provided with one or more sealsto facilitate the displacement, using a laser conductive fluid, of laserobstructing materials from the laser light path. The deflection membercomprises a guide member to engage and deflect the drill head and thesecond umbilical connected thereto to a targeted portion of the borewall. A deployable seal, which may be a circumferentially deployableseal, is disposed on the deflection member. Upon deployment of thedeployable seal, such as be fluid pressure provided through the fluidconduit of the first umbilical, the seal expands to engage the bore wallto generally isolate a portion of the bore wall to be extended from aportion of the bore system that contains laser obstructing materials.

The second umbilical comprises a leading end, to which the drill head isconnected, for being introduced into the bore system. The secondumbilical storage device feeds out the second umbilical into the boresystem in an amount sufficient to position the drill head at the leadingend of the second umbilical proximal a portion of a bore wall to beextended using the drill head. The drill head comprises one or morefluid injection ports to introduce fluid supplied through the fluidconduit of the second umbilical to displace laser obstructing materialsfrom a laser path intermediate the drill head and a targeted portion ofthe bore wall. Laser obstructing materials may include, but are notlimited to, working fluid, drilling fluid, formation fluids and otherfluids and debris, including debris generated by the laser drillingprocess. The laser light path, as that term is used herein, is the paththrough which the laser light emitted from the laser emitting portion ofthe drill head will beam to impinge on the targeted portion of the wallof the bore section to be extended using the drill head.

The drill head of the second umbilical may further comprise one or moreoptical elements at the laser emitting portion of the drill head tofocus and/or condition the laser light transmitted via the opticallytransmitting fibers of the second umbilical from the surface. Theoptical elements may focus and/or condition the laser light for optimalheating of the targeted portion of the bore wall. The optical elementsmay comprise lenses housed at the laser emitting portion of the drillhead and optically coupled to a leading end of optical fibers extendingfrom the second umbilical and terminating at or within the drill head.The optical elements may be housed, for example, at an end of the drillhead generally opposite a connected end of the drill head, and theoptical elements may be protected using a movable protective member orby a stationary and transparent protective member such as, for example,glass or polycarbonate, through which emitted laser light may pass toimpinge upon the targeted portion of the bore wall opposite the laserpath from the laser emitting portion of the drill head.

In one embodiment, the deflection member connected to the leading end ofthe first umbilical comprises at least one deployable circumferentialseal that is an inflatable member, and deployment of the seal may beimplemented by remotely opening a valve fluidically coupled between thedeployable seal and the leading end of the fluid conduit of the firstumbilical used to position the deflection member within the bore. In oneembodiment, the deployed seal may be retracted from the deployedconfiguration by closing the valve and by then remotely opening a secondvalve coupled to release the fluid from the deployed seal into the boresection. In another embodiment, the valve opened to introduce fluid fromthe fluid conduit to deploy the seal and the second valve coupled torelease fluid from the deployed seal to the bore may be replaced with asingle remotely-controllable three-way valve having a first selectableposition, to establish communication between the fluid conduit of theumbilical and the deployable seal to inflate the seal, and a secondselectable position to establish communication between the inflated sealand the bore section to deflate the seal.

The above-described system of the present invention comprises a drillhead which may be used to extend a bore section of a bore system. Meltedformation components and heated debris may be moved from the portion ofthe bore wall being extended to a portion of the bore having workingfluid or drilling fluid so that it may be circulated to the surface andthereby removed from the bore system. Alternately, the debris may beswept, using fluid injected from the drill head and at the portion ofthe bore wall being extended, to a debris removal passage of the drillhead where, using differential pressure, the debris is moved to a to thesurface or to a portion of the bore containing working fluid or drillingfluid.

In one embodiment, a portion of the second umbilical proximal to thedrill head connected at the leading end comprises an exterior portionwith a lining to facilitate engagement and controllable advance of thesecond umbilical. The second umbilical may comprise a fluid conduit anda plurality of optical fibers and, in some embodiments, a debris removalchannel. The exterior portion of the second umbilical is shaped andsized to be engaged and controllable advanced using a drive gearadjacent to an umbilical pathway of the deflection member through whichthe second umbilical passes. The operation of the drive gear in thedeflection member cooperates with the exterior portion of the secondumbilical to controllably advance and thereby position the drill headconnected at the leading end of the second umbilical for extending alateral bore.

FIG. 1 is a schematic illustrating an aspect of the system 10 of thepresent invention. A borehole 90 is drilled into the earth's crust 11 sothat a portion 17 of the borehole 90 penetrates a geologic formation 19bearing a fluid medium such as, for example, hydrocarbons. The system 10comprises a first coiled tubing unit 130 at the surface 15 having asource of fluid 112 such as, for example, water or pressurized gas, thatis fluidically coupled through a fluid leader 113 to a fluid conduit(not shown) within a first umbilical 134. The system 10 furthercomprises a second coiled tubing unit 30 at the surface 15 having asource of fluid 12 such as, for example, water or pressurized gas, thatis fluidically coupled through a fluid leader 13 to a fluid conduit (notshown) within a second umbilical 34. The system 10 further comprises aportable electric generator 14 electrically coupled through a powersupply leader 18 to power a laser light generator 16 that is, in turn,optically coupled through a laser leader 26 to a plurality of opticalfibers 47 (not shown in FIG. 1) within the second umbilical 34. Thesystem 10 of FIG. 1 comprises a wellhead 25 sealing the surface end 91of the bore 90 through which the first umbilical 134 and the secondumbilical 34 are received into the bore 90, a working fluid tank 20coupled through a working fluid leader 22 to the wellhead 25 to enablethe introduction and removal of working fluid 21 into and from anannulus 24 between the first umbilical 134 and the second umbilical 34,on the one hand, and the wall 94 of the bore 90, on the other hand. Thesystem further comprises a first spool 130 on which an extended lengthof the first umbilical 134 may be stored, a second spool 30 on which anextended length of the second umbilical 34 may be stored, and a coiledtubing unit guide support 27 to support an umbilical guide 38 having aplurality of rolling elements 37 therein to reduce friction of movementof the first umbilical 134 and the second umbilical 34 into and from thewellhead 25 and the bore 90.

The first coiled tubing unit 130 and the second coiled tubing unit 30 ofthe system 10 each comprise a rotatable axles 132 and 32, respectively,enabling the spooling out and the spooling in of the first umbilical 134and the second umbilical 34, respectively, using motors (not shown) andrelated gears (not shown). In FIG. 1, the first coiled tubing unit 130has been reeled out to introduce a sufficient length of the firstumbilical 134 through the wellhead 25 to position the deflection member50 connected to a leading end 36 of the first umbilical 134 adjacent toa desired lateral bore location (not shown), and a deployable seal 54has been deployed to engage the wall 94 of the bore 90 adjacent thereto.Also, the second coiled tubing unit 30 has been reeled out to introducea sufficient length of the second umbilical 34 through the wellhead 25to position the drill head (not shown) adjacent to a targeted portion ofthe wall 94 to be extended.

FIG. 2 is a perspective view of a second umbilical storage spool 32Athat can be used to store the second umbilical 34 of a system of thepresent invention by coiling the second umbilical 34 against theinterior wall 33 of the spool 32A. After a portion of the interior wall33 is covered with outer coils 42 of the second umbilical 34,additional, smaller coils can be disposed within the initial, outercoils 42 for additional storage capacity. FIG. 3 is a top view of aanother alternative umbilical storage spool 32B that can be used tostore the second umbilical 34 of a system of the present invention bywrapping coils 44 around an exterior wall 41 of a center post 38 of thespool 34B. After a portion of the exterior wall 41 is covered with coils44 of the umbilical 34, additional, larger coils can be disposed aboutthe initial, inner coil 40 for additional storage capacity. It will beunderstood that these storage spools can also be used in conjunctionwith the first umbilical 134 of the system 10, and that the selection ofthe second umbilical 34 for use in the illustrations of FIGS. 2 and 3 isnot exclusive.

FIG. 4 is a perspective view of a drill head 51 that can be connected toa leading end 34A of the second umbilical 34 and used to implement anaspect of the system 10 (not shown in FIG. 4) of the present invention.The drill head 51 comprises a plurality of optical elements 45 opticallycoupled to a plurality of elongate optical fibers 47 that opticallyconduct laser light (not shown) provided from the laser light source 16(not shown—see FIG. 1) through the laser leader 26 (not shown—seeFIG. 1) to a surface end (not shown—see FIG. 1) of the optical fibers47. The optical elements 45 in the drill head 51 of FIG. 4 are disposedin a generally concentric pattern within a leading end 56 of the drillhead 51. The optical elements 45 may be disposed in a number of variouspatterns or positions within the drill head 51.

The drill head of FIG. 4 further comprises at least one fluid injectionport 46 disposed within the leading end 56 of the drill head 51 andpositioned to inject a fluid provided through a fluid conduit 49 of thesecond umbilical 34 into a section of a bore (not shown in FIG. 4—seeFIG. 1) adjacent a bore wall (not shown) to be extended using laserlight (not shown) emitted from the optical elements 45 of the drill head51. In the drill head 51 of FIG. 4, the fluid injection port 46 isdisposed generally interior to a concentric pattern of optical elements45. The fluid injection port 46 or, in other embodiments of the drillhead 51, a plurality of fluid injection ports 46, may alternately bestrategically disposed in a variety of positions within the drill head51 to direct a stream of injected fluid into the bore section at aselected angle relative to an axis 62 of the drill head 51. The drillhead 51 of FIG. 4 optionally comprises an optional debris removalpassage 66 disposed to receive molten formation components and debrisfrom a laser-heated portion of a bore wall (not shown) and to convey thedebris (not shown) to the surface via the debris removal passage 66.

The second umbilical 34 illustrated in FIG. 4 and connected at itsleading end 34A to the drill head 51 further comprises an exteriorportion 67 having a series of corrugations 67A thereon that are sizedand shaped to be engaged by a drive motor (not shown) within thedeflection member 50 (not shown—see FIG. 5-8) with which the secondumbilical 34 cooperates to controllably advance the drill head 51 withina bore (not shown) to be extended using the drill head 51. An intervalof the exterior portion 67 is removed to reveal the opticallytransmitting fibers 47, the fluid conduit 49 and the optional debrisremoval passage 66 within the exterior portion 67 of the secondumbilical 34. It should be noted that the exterior portion 67 terminatesproximal to the leading end 34A of the second umbilical 34 and mayextend several meters (see, for example, FIG. 5) along the secondumbilical 34 from the drill head Si to facilitate controllable advanceand positioning of the drill head 51 within a bore (not shown) to beextended, as will be described in more detail in the paragraphs thatfollow.

FIG. 5 is an enlarged section view the deflection member 50 cooperatingwith the second umbilical 34 and the drill head 51 connected thereto ofone embodiment of the apparatus and system of the present inventionpositioned using a first umbilical 134 within a primary bore 90 to makeand/or extend an intersecting lateral bore 88 within a geologicformation 19. The deflection member 50 of FIG. 5 comprises an exteriorsurface 59, a proximal circumferentially deployable seal 54 and a distalcircumferentially deployable seal 154 to engage and seal against thewall 94 of the primary bore 90. The deflection member 50 furthercomprises a proximal end 89 and a distal end 93, and a lateral exit port95 therebetween. The deflection member further comprises a guide member76 therein to engage and deflect the drill head 51 to the lateral exitport 95 and a pair of drive gears 77 to engage the corrugations 67Aalong the exterior portion 67 of the second umbilical 34 to therebycontrollably advance the movement of the drill head 51 connected to thesecond umbilical 34. The space between the drive gears 77, the spacealong the guide member 76 and the lateral exit port 95 are portions ofan umbilical pathway 99 of the deflection member 50 that cooperates withthe second umbilical 34, specifically with the exterior portion 67 ofthe second umbilical 34, to locate and to extend the lateral boresection 88.

FIG. 6 is a side sectional elevation view of a portion of an alternativeembodiment of the deflection member 50 of the system 10 (not shown) ofthe present invention positioned in a primary bore 90 using a firstumbilical 134 (not shown) to cooperate with a second umbilical 34 (notshown) to extend a lateral bore section 88. The deflection member 50 maybe generally centrally located relative to the surrounding bore wall 94.The deflection member 50 of FIG. 6 comprises an alternativenon-circumferential deployable seal member 110 disposed to surround alateral exit port 95 in the deflection member 50. The seal member 110engages the bore wall 94 of the primary bore 90 to isolate the lateralbore section 88 and the lateral exit port 95.

FIG. 7 is a frontal elevation view of the alternative embodiment of thedeflection member 50 of FIG. 6 illustrating the view of the deflectionmember 50 and the non-circumferentially deployable seal member 110 fromthe right side of FIG. 6. FIG. 7 illustrates lateral exit port 95surrounded by the deployed non-circumferential seal member 110.

FIG. 8 is a top sectional view of the alternative embodiment of thedeflection member 50 of FIGS. 6 and 7. The deployed non-circumferentialseal member 110 is illustrated in FIG. 8 as wrapping around a portion ofthe deflection member 50 as it engages the bore wall 94 (not shown—seeFIG. 6) of the primary bore 90 as it surrounds the lateral bore section88 (not shown—see element 88 in FIG. 6.

FIG. 9 is a section view of an embodiment of a drill head 51 that can beconnected to a leading end of the second umbilical 34 (not shown—seeFIG. 5) to be positioned and controllably advanced within a lateral bore88 by operation of the drive gears 77 (not shown—see FIG. 5) of thedeflection member 50 (not shown—see FIG. 5). The drill head 51 of FIG. 9comprises an exterior surface 59 and a drill head fluid jumper conduit71 therein connected to the fluid conduit of the second umbilical 34(not shown in FIG. 6—see element 49 of FIG. 4) to supply fluid to afluid lateral 64 upon opening of a seal valve 63 to deliver fluid to acircumferentially deployable seal 54 to deploy the seal to engage andseal against the wall 94 of the bore section 88 when in the sealing modeillustrated in FIG. 9. The drill head 51 of FIG. 9 further comprises adeflation stem 60 having a seal deflation valve 61 to relieve pressurewithin the circumferentially deployable seal 54 to restore thedeployable seal 54 to a retracted mode (not shown in FIG. 9) todisengage the wall 94 of the bore section 88. The drill head 50 furthercomprises a debris removal passage 66 to remove debris 81 from meltedformation 19 components generated by the laser drilling process. Thedrill head fluid conduit 71 also supplies fluid to fluid jumper conduits49 to deliver fluid to fluid nozzles 46 that are positioned on the drillhead 51 to inject a fluid streams 75 anterior to and adjacent to laseremitting portions 45A of the drill head 51 adjacent to optical elements45 at the leading end 56 of the drill head 51. The fluid streams 75 aredirected to protect the laser emitting portions 45A from being fouledand contaminated by debris 81 being generated by the laser drillingprocess when laser light 52 is provided to the optical elements 45through optical fibers 47.

FIG. 10 is a section view of an alternative embodiment of a drill head51 of FIG. 9 comprising a transparent member 72 such as, for example, aglass or polycarbonate plate, disposed intermediate the laser emittingportion 45A of the optical elements 45 and the protective fluid stream75. The transparent member 72 provides additional protection to thelaser emitting portions 45A of the optical elements 45. The fluidstreams 75 injected from the nozzles 46 provide a protective barrier forthe transparent member 72 and the fluid streams 75 may impinge upon andthereby provide for debris removal for any debris that may adhere to thetransparent member 72. As a result, drilling efficiency is maintained bymaintaining the intensity of the laser light 52 that impinges on thewall 94 of the bore 88.

FIG. 11 is a section view of an alternative embodiment of a drill head51 that can be used in the system of FIG. 1 having generally rigidprotective barriers 73 disposed to protect the laser emitting portions45A of the optical elements 45 of the drill head 51 when the protectivebarrier 73 is in the closed position illustrated in FIG. 11. Theprotective barriers 73 are disposed anterior to an opening or nozzle 87(not shown in FIG. 11—see FIGS. 12-15) in a drill head structure 53 ofthe drill head 51 to which the protective barriers 73 may be coupled.

FIG. 12 is an enlarged view of one of the optical elements 45 of FIG. 11having a protective barrier 73 of FIG. 11 and revealing a hinge 74disposed intermediate the rigid protective barrier 73 and a drill headstructure 85 of the drill head 51 to facilitate pivoting of theprotective barrier 73 between the closed position, illustrated in FIG.11 to protect a laser emitting portion 45A, and an open positionillustrated in FIG. 13. The protective barrier 73 may be biased to theclosed position using a spring element 86 and it may be coupled to thedrill head structure 85 using a fastener 84. The protective barrier 73is disposed anterior to an opening or nozzle 87 in the closed positionillustrated in FIG. 12.

FIG. 13 is the protective barrier 73, the optical element 45 and theplurality of optical fibers 47 of FIG. 12 after pressurized fluid isprovided through the fluid jumper conduit 49 to the opening 87 in thedrill head structure 85. The fluid pressure resulting from the fluidspray 75 introduced through the opening 87 displaces the protectivebarrier 73 against the spring element 86 from the closed position ofFIG. 12 to the open position of FIG. 13 to open a laser light pathway 52to the laser emitting portion 45A of the optical element 45.

FIG. 14 is an alternative embodiment of the apparatus of the presentinvention comprising an optical element 45, a laser emitting surface 45Aand a plurality of cooperating protective barrier portions 82 and 83coupled to the drill head structure 85 using fasteners 84. Thecooperating protective barrier portions 82 and 83 may compriseelastomeric elements such as, for example, temperature-resistant rubberand rubberized materials, that are biased to a relaxed, closed positionshown in FIG. 14. The cooperating protective barrier portions 82 and 83are positioned to engage one against the other to together provide aprotective barrier to prevent debris from fouling or otherwise impairingemissivity of the laser emitting portion 45A. The cooperating protectivebarrier portions 82 and 83 cooperating protective member portions 82 and83 are disposed adjacent to an opening 87 in the drill head structure85.

FIG. 15 are the protective barriers 82 and 83, the optical element 45and the plurality of optical fiber 47 of FIG. 14 after pressurized fluidis provided to the opening 87 in the drill head structure 85 to whichthe protective barrier portions 82 and 83 are fastened using fasteners84. The fluid pressure resulting from the fluid spray 75 introducedthrough the opening 87 displaces the protective barriers portions 82 and83 from the closed position of FIG. 14 to the open position of FIG. 15to open a laser light pathway 52 to the laser emitting portion 45A ofthe optical element 45.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, a “set” may comprise a single member or a plurality ofmembers. For example, a set of coolant injection ports or a set of gasinjection ports may comprise a single coolant injection port or a singlegas injection port or it may comprise a plurality of coolant injectionports or gas injection ports.

As used herein, the term “fluid” refers to either liquid or gas. It willbe understood that, in embodiments of the system and/or apparatus of thepresent invention providing a stream of injected fluid to cool, cleanand/or protect a laser emitting portion of a drill head or a protectivebarrier positioned adjacent to a laser emitting portion of a drill head,it is advantageous for the injected fluid to be transparent or opaquesuch as, for example, water, nitrogen gas, carbon dioxide gas, an inertgas, and the like. It is preferred that the fluid not be corrosive orotherwise damaging to the drill head or to the formation face exposed inthe drilling process. A fluid nozzle may be a nozzle that shapes theinjected stream of fluid into a broad, flattened barrier for optimalprotection and coverage.

As used herein, the term “working fluid” refers to a fluid introducedinto the bore system for the purpose of lubricating the bore system tofacilitate the smooth insertion, positioning and removal of theapparatus comprising the drill head, for the purpose of hydrostaticallyopposing or balancing formation pressure to minimize the potential forwell control problems due to an unwanted and unexpected influx offormation fluids into the bore.

As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises” and/or “comprising,” when used in thisspecification, specify the presence of stated features, integers, steps,operations, elements, components and/or groups, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof. The terms“preferably,” “preferred,” “prefer,” “optionally,” “may,” and similarterms are used to indicate that an item, condition or step beingreferred to is an optional (not required) feature of the invention.

The corresponding structures, materials, acts, and equivalents of allmeans or steps plus function elements in the claims below are intendedto include any structure, material, or act for performing the functionin combination with other claimed elements as specifically claimed. Thedescription of the present invention has been presented for purposes ofillustration and description, but it is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiment was chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

We claim:
 1. A system comprising: a first umbilical having an elongatefluid conduit having a leading end and a surface end; a fluid sourcecoupled to a surface end of the fluid conduit of the first umbilical; adeflection member connected to a leading end of the first umbilical andhaving a drive gear, a proximal end, a distal end, a laterally directedexit port intermediate the proximal and distal ends, and at least onedeployable seal having at least a portion disposed intermediate theproximal end and the laterally directed exit port; a second umbilicalhaving a plurality of elongate optically transmitting fibers and anexterior portion having sized and shaped to be engaged and moved by thedrive gear of the deflection member in a direction generally coincidentwith a portion of an axis of the second umbilical adjacent to the drivegear; a laser light power generator optically coupled to a surface endof the plurality of optically transmitting fibers; and a drill headconnected to a leading end of the second umbilical and having an opticalelement to condition laser light received through the opticallytransmitting fibers of the second umbilical; wherein the deflectionmember is positionable within a primary bore using the first umbilical;and wherein the second umbilical is receivable through an umbilicalpathway adjacent the drive gear and through the lateral exit port of thedeflection member, and movable through the pathway by operation of thedrive gear to engage and advance the exterior portion of the secondumbilical to advance the drill head to extend a lateral bore formedlaterally adjacent to the lateral exit port.
 2. The system of claim 1wherein the at least one deployable seal is energized to a deployedcondition using fluid pressure provided through the fluid conduit. 3.The system of claim 1 wherein the gear drive is operable using fluidpressure provided through the fluid conduit to move the second umbilicalalong the umbilical pathway of the deflection member.
 4. The system ofclaim 1 wherein the second umbilical exterior portion comprises a seriesof radially-protruding corrugations sized and shaped to engage the drivegear of the deflection member; wherein the corrugations along theexterior portion of the second umbilical radially protrude in a planegenerally perpendicular to the adjacent portion of an axis of the secondumbilical.
 5. The system of claim 1 wherein the second umbilicalexterior portion comprises a spiraling thread sized and shaped to engagethe drive gear of the deflection member; wherein the pitch and depth ofthe spiraling thread matches the pitch and depth of a mating thread onthe drive gear.
 6. The system of claim 1 further comprising: a sealbypass conduit of the deflection member having an inlet distal to thelateral exit port and an outlet proximal to the at least one deployableseal.
 7. The system of claim 1 wherein the leading end of the fluidconduit discharges fluid provided into the surface end of the fluidconduit to a portion of the primary bore distal to the at least onedeployable seal to displace fluid through the seal bypass conduit to aportion of the primary bore proximal to the at least one deployable sealto facilitate removal of laser-obstructing materials from a laser lightpath intermediate the laser emitting portion of the drill head and atargeted portion of a bore wall.
 8. The system of claim 1, wherein theat least one deployable seal comprises: a proximal deployable sealintermediate the proximal end and the lateral exit port of thedeflection member; a distal deployable seal on the deflection memberintermediate the distal end and the lateral exit port of the deflectionmember; a distal deployable seal bypass conduit of the deflection memberhaving an inlet intermediate the lateral exit port and the distaldeployable seal and an outlet distal to the distal deployable seal; anda deflection member bypass conduit of the deflection member having afirst end distal to the distal deployable seal and a second end proximalto the proximal deployable seal to equalize pressure between the portionof the primary bore intermediate the deflection member and the surfaceand the portion of the primary bore opposite the deflection memberthereto.
 9. The system of claim 8, wherein fluid displaced from thesurface through the fluid conduit and from the leading end of the fluidconduit after deployment of the proximal and distal deployable sealsdisplaces at least some material captured by deployment of the proximaland distal deployable seals in an interval intermediate the proximal anddistal deployable seals through the distal deployable seal bypass to theportion of the primary bore distal to the deflection member.
 10. Thesystem of claim 8, further comprising: a check valve disposed within thedistal deployable seal bypass conduit to prevent flow from the outlet ofthe distal deployable seal bypass to the inlet of the distal deployableseal bypass.
 11. The system of claim 1, further comprising: an elongatecontrol conduit of the first umbilical; a seal deployment valvepositionable in response to an activation signal provided through thecontrol conduit between a closed position and an open position toprovide fluid to the proximal deployable seal.
 12. The system of claim1, wherein the fluid provided into the surface end of the fluid conduitis one of a pressurized gas and a non-laser-obstructing liquid.
 13. Thesystem of claim 12 wherein the fluid is a pressurized gas comprising atleast one of an inert gas, carbon dioxide and nitrogen.
 14. The systemof claim 12 wherein the fluid is a non-laser-obstructing fluidcomprising at least one of ionized water, deionized water, potassiumchloride, inhibited glycol and water solutions, and a dielectric fluid.15. A drill head, comprising: an optical element connectable to anoptically transmitting fiber to emit laser light to impinge on atargeted portion of a wall of an earthen bore section; and a fluidnozzle positioned adjacent the optical element and directed to emit astream of fluid anterior to and proximal to a laser emitting portion ofthe optical element to provide a protective fluid barrier.
 16. The drillhead of claim 15, further comprising: a second optical elementconnectable to a second optically transmitting fiber to emit laser lightto impinge on the targeted portion of the wall of the bore section; anda second fluid nozzle positioned adjacent the second optical element anddirected to emit a second stream of fluid anterior to and proximal to asecond laser emitting portion of the second optical element to provide aprotective fluid barrier.
 17. The drill head of claim 15, furthercomprising: a trailing end of the drill head opposite the laser emittingportion and connectable to an optically transmitting fiber of anumbilical to provide laser light from a laser light generator at theearth's surface to the optical element and to a fluid conduit to providea fluid from a source at the earth's surface to the fluid nozzle. 18.The drill head of claim 15, wherein the fluid nozzle is directed toimpinge the fluid stream emitted therefrom onto an outer surface of thelaser emitting portion of the optical element.
 19. The drill head ofclaim 15, further comprising: a transparent barrier disposed anterior tothe laser emitting portion of the optical element of the drill head toprotect the optical element from contamination by elements presentwithin an earthen bore section.
 20. The drill head of claim 19, whereinthe transparent barrier comprises at least one of glass and apolycarbonate material.
 21. The drill head of claim 19, furthercomprising: a fluid jumper conduit within the drill head and having afirst portion connectable to a leading end of a fluid conduit to providea stream of fluid flow through the fluid nozzle and onto the transparentbarrier to remove heat generated by laser light emitted through thetransparent barrier.
 22. The drill head of claim 21, further comprising:an outlet from the fluid jumper conduit connected to the fluid nozzle;wherein the fluid nozzle provides a fluid barrier to protect thetransparent barrier.